/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Mechanics/RectangleMarqueeMechanic.h
Note: This function is in the public API to optimize selection in the UV editor where meshes are known to lie in the XY plane in front of the camera (so point projection/camera plane clipping is unnecessary)
[FRectangleInPlane](API\Plugins\ModelingComponents\Mechanics\FCameraRectangle\FRectangleInPlane) ProjectSelectionDomain ( double OffsetFromCameraPlane ) const